Estimating sample-domain distortion in the transform domain with rounding compensation
US8059721B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 7, 2006 |
| Grant date | Nov 15, 2011 |
| Priority date | — |
| Expiry date | Nov 23, 2029 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N19/61
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
Techniques and tools are described for compensating for rounding when estimating sample-domain distortion in the transform domain. For example, a video encoder estimates pixel-domain distortion in the transform domain for a block of transform coefficients after compensating for rounding in the DC coefficient of the block. In this way, the video encoder improves the accuracy of pixel-domain distortion estimation but retains the computational advantages of performing the estimation in the transform domain. Rounding compensation includes, for example, looking up an index (from a de-quantized transform coefficient) in a rounding offset table to determine a rounding offset, then adjusting the coefficient by the offset. Other techniques and tools described herein are directed to creating rounding offset tables and encoders that make encoding decisions after considering rounding effects that occur after an inverse frequency transform on de-quantized transform coefficient values.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.